The study looked at how a rule requiring governments to not spend more than they earn affects public debt. The researchers found that this rule leads to a gradual decrease in debt levels, as lawmakers reduce debt when demand for public services is low. However, whether this rule benefits citizens depends on whether the lower debt burden outweighs the drawbacks of higher tax volatility and less public services. The study used a model to quantify these costs and benefits, showing that imposing the rule can lead to a loss in overall welfare if the initial debt level is already low.